What is dementia?

What is dementia?
If you, or a friend or relative, have been confused. You may not know what dementia is. This factsheet should help answer some of yourquestions about dementia, including what causes it and how it is diagnosed.
The term 'dementia' describes a set of symptoms which include loss of memory, mood changes, andproblems with communication and reasoning. These symptoms occur when the brain is damaged bycertain diseases, including Alzheimer's disease and damage caused by a series of small strokes.
Dementia is , which means the symptoms will gradually get worse. How fast dementiaprogresses will depend on the individual person and what type of dementia they have. Each person isunique and will experience dementia in their own way. It is often the case that the person's family andfriends are more concerned about the symptoms than the person may be themselves.
- Loss of memory - this particularly affects short-term memory, for example forgetting what
happened earlier in the day, not being able to recall conversations, being repetitive orforgetting the way home from the shops. Long-term memory is usually still quite good.
- Mood changes - people with dementia may be withdrawn, sad, frightened or angry about
- Communication problems - including problems finding the right words for things, for example
describing the function of an item instead of naming it.
, the person affected will have problems carrying out everyday tasksand will become increasingly dependent on other people.What causes dementia?
There are several diseases and conditions that result in dementia. These include:
disease the chemistry and structure of the brain change, leading to the death of brain cells.Problems of short-term memory are usually the first noticeable sign.
cells are likely to die and this can cause the symptoms of vascular dementia. Thesesymptoms can occur either suddenly, following a stroke, or over time through a series of
structures that develop inside nerve cells. Their presence in the brain leads to thedegeneration of brain tissue. Symptoms can include disorientation and hallucinations, as wellas problems with planning, reasoning and problem solving. Memory may be affected to alesser degree. This form of dementia shares some characteristics with Parkinson's disease.
is usually focused in the front part of the brain. At first, personality and behaviour changesare the most obvious signs.
Rarer causes of dementia
palsy, Korsakoff's syndrome, Binswanger's disease, HIV/AIDS, and Creutzfeldt-Jakob disease (CJD).Some people with multiple sclerosis, motor neurone disease, Parkinson's disease and Huntington'sdisease may also develop dementia as a result of disease progression.Mild cognitive impairment
Some individuals may have noticed problems with their memory, but a doctor may feel that the are not severe enough to warrant a diagnosis of Alzheimer's disease or another type ofdementia, particularly if a person is still managing well. When this occurs, some doctors will use theterm 'mild cognitive impairment' (MCI). Recent research has shown that individuals with MCI have anincreased risk of developing dementia. The conversion rate from MCI to Alzheimer's is 10-20 per centeach year, so a diagnosis of MCI does not always mean that the person will go on to developdementia.Who gets dementia?
- There are about 800,000 people in the UK with dementia.
- Dementia mainly affects people over the age of 65 and the likelihood increases with age.
However, it can affect of 65 who have dementia.
- Scientists are investigating the genetic background to dementia. It does appear that in a few
rare cases the diseases that cause dementia can be inherited. Some people with a particulargenetic make-up have a higher risk than others of developing dementia.
Can dementia be cured?
Most forms of dementia cannot be cured, although vaccines and other . Drugs have been developed that can temporarily alleviate some of thesymptoms of some types of dementia. These drugs include the three acetylcholinesterase inhibitors:
Alzheimer's disease
In March 2011, the National Institute for Health and Clinical Excellence (NICE) issued revisedguidance on treatment, recommending that people in the mild-to-moderate stages of Alzheimer'sdisease should be given treatment with one of the acetylcholinesterase inhibitors.
The latest NICE guidance also recommends a different type of drug (memantine, trade name Ebixa)for people with severe Alzheimer's and some of those with moderate disease. For more information,
Dementia with Lewy bodies
may be offered an acetylcholinesterase inhibitor if theirnon-cognitive symptoms, such as hallucinations, delusions or associated aggressive behaviour, arevery distressing. Vascular dementia
clinical trial. This is because of a lack of evidence that these drugs are effective for symptoms ofvascular dementia. Treatment should be aimed at the underlying cardiovascular (heart and circulatory)problems.How can I tell if I have dementia?
Many people fear they have dementia, particularly if they think that their is getting worse or ifthey have known someone who has had the illness. Becoming forgetful does not necessarily meanthat you have dementia: memory loss can be an effect of ageing, and it can also be a sign of stress ordepression. In rare cases, dementia-like symptoms can be caused by vitamin deficiencies and/or abrain tumour. If you are worried about yourself, or someone close to you, it is worth discussing yourconcerns with your GP.Diagnosing dementia
might have similar symptoms to dementia, including depression. Having a diagnosis may also mean itis possible to be prescribed drugs for Alzheimer's disease. Whether you are someone with dementiaor a carer, a diagnosis can help with preparing and planning for the future.
Dementia can be diagnosed by a doctor - either a GP or a specialist. The specialist may be ageriatrician (a doctor specialising in the care of older people), a neurologist (someone whoconcentrates on diseases of the nervous system) or a psychiatrist (a mental health specialist). Thedoctor may carry out a number of tests to check basic thinking processes and the ability to performdaily tasks. They may request further tests, such as a brain scan or a more in-depth assessment ofmemory, concentration and thinking skills.Can dementia be prevented?
At present, it is not clear what causes most of the diseases that lead to dementia. It is not clear whatcan be done to prevent dementia itself but the evidence does indicate that a healthy diet and lifestylemay help protect against dementia. In particular, exercising regularly, avoiding fatty foods, notsmoking, drinking alcohol in moderation and keeping mentally and socially active into old age mayhelp to of developing vascular dementia and Alzheimer's disease.Further reading
Alzheimer's Society produces factsheets on a wide range of topics, including:
For details of Alzheimer's Society services in your area, visit
Factsheet 400
Last reviewed: April 2011, updated: March 2012Next review due: April 2013
Reviewed by Dr Sebastian Crutch, Dementia Research Centre, UCL Institute of Neurology and DrYvonne McCulloch, Clinical Health Psychology & Neuropsychology Department, Charing CrossHospital, London
Alzheimer's Society National Dementia Helpline
England, Wales and Northern Ireland: 0300 222 11 22
Registered charity no. 296645. A company limited by guarantee and registered in England no. 2115499.